类金钢石非晶碳薄膜的光吸收和光致发光研究

我们用激光轰击石墨靶成功地制备出类金刚石无氢非晶碳薄膜.测量了光学吸收、光致发光及其随入射光强度的变化关系.结果表明,这种薄膜具有类金刚石的性质,光学带隙在1.67-2.25eV,发光在可见光区呈宽带结构.低激发强度下发光强度超线性变化,而在高激发强度下则为线性发光.我们用非成对载流子复合的模型对结果给出了合理的解释.用带尾态饱和的模型解释了发光峰值随激发光强增加而蓝移的现象.

STUDY OF OPTICAL ABSORPTION AND PHOTOLUMINESCENCE OF DIAMOND-LIKE FILMS

Diamond-like films were prepared by laser ion beam deposition technique, and the optical absorption, photoluminescence and the dependence of photoluminescence on incident light intensity were measured. Our experimental results indicate that optical gaps vary in the range of 1.67-2.25eV,and the photoluminescance spectrum is a broad band with peak position in the range of visible light. The facts that superlinear luminescence photooxcited by lower incident light intensity and linear luminescencs photoexcited by higher incident light intensity have been explained in terms of the model of nongeminate radiative recombination. Using the model of tail state saturation we also illustrate the fact of blue shift of photoluminescence paak position when increasing the incident light intensity.